Field of the Invention
The present invention relates to an X-ray fluoroscopic device to be used relative to a radiation therapy apparatus for performing a radiation therapy by irradiating a therapy beam to a subject, a dynamic (moving) body tracking device and an X-ray detector.
Description of the Related Art
A radiation must be irradiated exactly to an affected region relative to the radiation therapy apparatus, having a head that irradiates the therapeutic beam and a gantry to rotate the head around a subject as the center, that performs a radiation therapy by irradiating the therapeutic beam, including e.g., X-ray and an electron beam and so forth to the affected region such as a tumor and so forth. Nevertheless, in some cases, not only the subject unintentionally may move the body thereof, but also the affected area per se may move. For example, a tumor near the lung largely moves depending on breathing. Accordingly, a radiation therapeutic device comprising a mechanism, in which the X-ray fluoroscopic device detects the position of a metal marker in-place near the tumor and then the therapeutic radiation to be irradiated is controlled thereby, is disclosed (referring to Patent Document 1).
As such radiation therapy apparatus, an X-ray fluoroscopy apparatus that identifies the location of the marker by fluoroscoping the image including the marker implanted inside the body of the subject. According to such X-ray fluoroscopy device, an implanted marker inside body by a template matching and so forth by using a first fluoroscopic mechanism including a first X-ray tube that irradiates an X-ray from the floor surface side and a first X-ray detector that detects the X-ray passing through the subject from the ceiling side and a second fluoroscopic mechanism including a second X-ray tube that irradiate an X-ray from the floor surface side and a second X-ray detector that detects the X-ray passing through the subject from the ceiling side. And 3-dimensional positional data can be acquired by utilizing a 2-dimensional fluoroscopy image imaged by the first fluoroscopic mechanism and a 2-dimensional fluoroscopy image imaged by the second fluoroscopic mechanism. Accordingly, the dynamic tracking to detect the moving maker of the region with a high degree of accuracy can be performed by continuously performing such operations and calculating the real-time 3-dimensional positional data. And an irradiation of the therapeutic radiation is controlled based on the positional data of the marker acquired by such dynamic body tracking so that the irradiation of the radiation corresponding to such move of the tumor can be performed with a high degree of accuracy.
FIG. 12 is a schematic view illustrating the state in which a radiation therapy is being conducted by a radiation therapeutic device having a traditional fluoroscopy apparatus.
The present radiation therapeutic apparatus is to provide a therapeutic treatment by irradiating an X-ray or an electron beam to the affected area of the subject 57 lying on the table 56 and comprises a head 55 in order to irradiate the therapeutic beam B toward the subject 57. In addition, such radiation therapeutic apparatus comprises a first X-ray fluoroscopic mechanism consisting of the first X-ray tube 1a and the first X-ray detector 2a and a second X-ray fluoroscopic mechanism consisting of the second X-ray tube 1b and the second X-ray detector 2b so that fluoroscopy an image including the marker inside the subject 57 in order to perform a dynamic body tracking can be performed.
According to the aspect of such radiation therapy apparatus, the therapeutic beam B that is irradiated from the head 55 to the subject 57 becomes scattered radiation S and then is incident into the first X-ray detector 2a and the second X-ray detector 2b. When such scattered radiation S is incident into the first X-ray detector 2a and the second X-ray detector 2b, an artifact takes place in the image imaged by the first X-ray detector 2a and the second X-ray detector 2b, so that it is problematic that the dynamic body tracking can be interrupted.
Therefore, according to the aspect of an radiation therapy apparatus disclosed in Patent Document 1, an irradiation of the therapeutic beam B and an irradiation of the X-ray for dynamic body tracking are synchronized and the gate of the image intensifier (I. I.) is turned on except the irritation of the X-ray to perform the dynamic body tracking by utilizing a function of the image intensifier as the X-ray detector so that the scattered radiation S due to the therapeutic beam B cannot be received and the irradiation of the therapeutic beam B can be suspended when the X-ray is irradiated.